It is believed that bollard luminaires are so named because in shape they tend to resemble the bollards, i.e., posts, used at wharfs and around which mooring lines are fastened. Bollard luminaires provide ground (or floor) level illumination over a relatively large area. In some instances, bollard luminaires provide only "uplighting" for illuminating ceilings which themselves reflect a portion of such light.
Bollard or bollard-type luminaires are shown in several patents including U.S. Pat. No. 4,041,305 (Dean) which shows a bollard-type luminaire using one-way reflective glass. Such luminaire uses four radial, reflective baffles and a lamp positioned generally in line with the light opening.
U.S. Pat. No. 4,768,139 (Poppenheimer) shows a ground stake mounted luminaire in which the lamp is positioned above a cone-shaped reflector and below a "mushroom-shaped" reflector. At least a significant portion of the light appears to be projected directly outward from the luminaire without being reflected. In another embodiment, much of the light is reflected outward by a curved reflector cup.
The luminaire shown in U.S. Pat. No. 3,646,338 (Goytisolo) uses a system of prisms and reflectors to direct light. Some light from the lamp emerges generally downward from the luminaire without contacting a prism or reflector. Other light is directed through a prism, yet other light is both reflected and directed through a prism while some light is only reflected from the top concave reflector.
The fixture shown in U.S. Pat. No. 4,787,018 (Poyer) uses a U-shaped fluorescent tube to produce light which radiates directly outward through a cylindrical frosted lens. No reflective or prismatic features are shown.
The optical system shown in U.S. Pat. No. 4,591,960 (Jones) uses four angled reflective surfaces to direct light from the lamp generally downward to the surrounding area. Such surfaces are arranged so that the lamp is not seen (or, perhaps, only barely seen) by passers-by. Reflected rays are concentrated to define a relatively "sharp" lobe.
The bollard luminaire shown in U.S. Pat. No. 4,438,484 (Winden) uses a resilient mount within the housing and impact resistant windows to help protect the luminaire against vandalism. The lamp is positioned adjacent the light openings and no reflectors are used. The light opening(s) provide a light pattern extending less than 360.degree. around the luminaire.
U.S. Pat. No. 4,447,864 (Smith et al.) shows a post-top luminaire with a cylindrical refractor-type lens and a top cover which is apparently translucent. The lamp is positioned adjacent the light opening and the lens and cover are held in place by fastener rods.
The luminaire shown in U.S. Pat. No. 4,231,080 (Compton) uses several stacked reflectors, some of which are concave, to direct light outward in a pattern of varying intensity, depending upon the angle at which such intensity is measured. The lamp appears to be exposed to the atmosphere.
U.S. Pat. Nos. 4,229,782 (Ruud et al.) and 4,386,392 (Reibling) show what appear to be indoor bollard luminaires for providing uplighting toward a ceiling.
While such bollard luminaires have been generally satisfactory, they have certain disadvantages. For example, the luminaires shown in the Dean, Winden and Smith et al. patents all have some sort of light-obstructing structure which interferes with uniform projection of light in a 360.degree. pattern about the luminaire. Others, like those shown in the Goytisolo, Jones and Compton patents use a lamp exposed to the environment. At the least, such lamp is thereby much more prone to damage by vandals and, perhaps, by cold blowing snow or rain.
Other luminaires provide area lighting at ground level but include no provision for uplighting useful to softly highlight foliage or architectural features. See, for example, the luminaires shown in the Dean, Peppenheimer, Goytisolo, Jones, Winden and Compton patents and, probably, the Poyer patent. Others like those shown in the Reibling and Ruud et al. patents provide only uplighting.
The bollard luminaire shown in the attached Gardco Lighting catalog mount the lamp socket, lamp and (necessarily) some wiring in the upper cover of the luminaire. At least the wiring tends to block passage of light and the lamp seems especially susceptible to being damaged by striking the top of the luminaire.
And, of course, any bollard luminaire having areas around the lamp and reflector to which insects can gain access will, over time, deteriorate in output. Such deterioration is due to "specking" and/or to the pile-up of insect bodies around the lamp and reflective surface.
An improved bollard luminaire which avoids or minimizes such disadvantages would be an important advance in the art.